bpf: don't let ldimm64 leak map addresses on unprivileged

[mirror_ubuntu-zesty-kernel.git] / kernel / ucount.c

diff --git a/kernel/ucount.c b/kernel/ucount.c
index 4bbd38ec37886d3d104e3d37dc80d101ab3767ac..c761cdba2a2d816b70ee1dcb4f2c0ffcf056df43 100644 (file)
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -139,7 +139,7 @@ static struct ucounts *get_ucounts(struct user_namespace *ns, kuid_t uid)
 
                new->ns = ns;
                new->uid = uid;
-               atomic_set(&new->count, 0);
+               new->count = 0;
 
                spin_lock_irq(&ucounts_lock);
                ucounts = find_ucounts(ns, uid, hashent);
@@ -150,8 +150,10 @@ static struct ucounts *get_ucounts(struct user_namespace *ns, kuid_t uid)
                        ucounts = new;
                }
        }
-       if (!atomic_add_unless(&ucounts->count, 1, INT_MAX))
+       if (ucounts->count == INT_MAX)
                ucounts = NULL;
+       else
+               ucounts->count += 1;
        spin_unlock_irq(&ucounts_lock);
        return ucounts;
 }
@@ -160,13 +162,15 @@ static void put_ucounts(struct ucounts *ucounts)
 {
        unsigned long flags;
 
-       if (atomic_dec_and_test(&ucounts->count)) {
-               spin_lock_irqsave(&ucounts_lock, flags);
+       spin_lock_irqsave(&ucounts_lock, flags);
+       ucounts->count -= 1;
+       if (!ucounts->count)
                hlist_del_init(&ucounts->node);
-               spin_unlock_irqrestore(&ucounts_lock, flags);
+       else
+               ucounts = NULL;
+       spin_unlock_irqrestore(&ucounts_lock, flags);
 
-               kfree(ucounts);
-       }
+       kfree(ucounts);
 }
 
 static inline bool atomic_inc_below(atomic_t *v, int u)
@@ -227,11 +231,10 @@ static __init int user_namespace_sysctl_init(void)
         * properly.
         */
        user_header = register_sysctl("user", empty);
+       kmemleak_ignore(user_header);
        BUG_ON(!user_header);
        BUG_ON(!setup_userns_sysctls(&init_user_ns));
 #endif
        return 0;
 }
 subsys_initcall(user_namespace_sysctl_init);
-
-